<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>

<body>
    <div ng-app="myApp" ng-controller="myCtrl">
        <ul>
            <li ng-repeat="x in text">
                {{ x | myFormat }}
            </li>
        </ul>
    </div>
    <script src="http://cdn.static.runoob.com/libs/angular.js/1.4.6/angular.min.js"></script>
    <script>
        var app = angular.module('myApp', []);
        app.service('checktext', function() {
            this.myFunc = function(x) {
                if (x.length < 4) {
                    return x;
                } else {
                    return "超过规定长度";
                }

            }
        });
        app.filter('myFormat', ['checktext', function(checktext) {
            return function(x) {
                return checktext.myFunc(x);
            }
        }]);
        app.controller('myCtrl', function($scope) {
            $scope.text = ['teafefewf', 'fsa', 'ew', 'fwafa', 'f'];
        });
    </script>
</body>

</html>